To clear up one of your points: ASIC = a chipset designed to perform a calculation. People here refer to ASICs as things designed to mine bitcoin and do literally nothing else. Problem is that when technology advances to such a stage when 3 TH/s is the slowest thing on the market, you won't get much return for your money spent.

If you want to mine, choose an altcoin and convert the profits to BTC. Here's a place to start http://www.coinchoose.com/